From: ShuoX Liu <shuox.liu@intel.com>
Date: Wed, 28 Mar 2012 22:19:11 +0000 (-0700)
Subject: cpuidle: add a sysfs entry to disable specific C state for debug purpose.
X-Git-Tag: v3.4-rc1~18^2~3^4~5
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3a53396b0381ec9d5180fd8fe7a681c8ce95fd9a;p=pandora-kernel.git

cpuidle: add a sysfs entry to disable specific C state for debug purpose.

Some C states of new CPU might be not good.  One reason is BIOS might
configure them incorrectly.  To help developers root cause it quickly, the
patch adds a new sysfs entry, so developers could disable specific C state
manually.

In addition, C state might have much impact on performance tuning, as it
takes much time to enter/exit C states, which might delay interrupt
processing.  With the new debug option, developers could check if a deep C
state could impact performance and how much impact it could cause.

Also add this option in Documentation/cpuidle/sysfs.txt.

[akpm@linux-foundation.org: check kstrtol return value]
Signed-off-by: ShuoX Liu <shuox.liu@intel.com>
Reviewed-by: Yanmin Zhang <yanmin_zhang@intel.com>
Reviewed-and-Tested-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
---

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